CRS issue20-online - Flipbook - Page 13
THE CRS PRODUCT GUIDE
BG SURGE PROTECTION DEVICES
18th New Regulations –
Surge Protection Devices
18th Edition Wiring Regulation
Main Switch SPD
Currently SPD devices are installed if written into the
installation specifications or if the installation is
deemed to be a high risk area, e.g. high rise buildings,
overhead cables etc., and normally only at the intake
position of the building, not at secondary distribution
points, but things are about to change...
The introduction of the 18th Wiring Regulations BS7671
and will come into force on the 1st January 2019.
There have been two major areas of interest within this
publication: 1) The introduction of Surge Protection devices
in domestic installations (SPD); 2) Arc Fault Detection
Devices in domestic installations (AFDD).
SPD’s have now been introduced as a mandatory
requirement into the 18th edition wiring regulations
for domestic installations.
The two major product related changes for the 18th
edition wiring regulations are listed below:
The installer now has to carry out a localised risk
assessment of the property and its electrical supply, this
exercise will determine if the SPD is a requirement or not.
zThe introduction of SPD (surge protection device)
as a requirement based on the risk assessment criteria
for domestic installations.
The risk assessment is based upon the properties
geographical location, the amount of lightning flashes
per year and how the incoming electrical supply enters
the building. All of these factors have an outcome which
determines if an SPD is a requirement.
zThe recommended use of AFDD (arc fault detection
device) in certain areas of domestic/commercial
& industrial buildings.
SPD Type 1 & 2 2 module TT and TNCS
SPD Type 2, 1 module
CUSPDA01 SPD Accessory cable stacking kit each
100A Main Switch + SPD Type 2
+ SPD Protection 32A MCB
CFUSW05SPD 5 Way
CFUSW08SPD 8 Way
CFUSW12SPD 12 Way
CFUSW15SPD 15 Way
CFUSW18SPD 18 Way
Dual RCD SPD
installed to BS EN
Type 1 SPD
boards >10m cable
Type 2 SPDs
Groups of individuals?
Dual RCD Units, 100A Main Switch
2 x 100A Type A RCD’s, SPD Type 2 + SPD
Protection 32A MCB
CFUD1000011ASPD 11 Way
CFUD1000014ASPD 14 Way
Main Switch Isolator
Type 3 Surge
as part of
AQ value or risk
* According to BS 7671 (443.2.4 note 2), there is no need to perform a risk assessment calculation for levels of consequence,
because this calculation always leads to the result that protection is required.
Note :- Within section 534 there is the 10m rule, about the voltage protection level of an SPD. E.g. if there was an SPD in the
consumer unit, after this point the SPD has an effective protection distance of up to 10m as defined in the BS7671 amendment
1, this means that a PC in a study >10m from the main SPD will need local over voltage protection. This can be provided by
standard surge protection extension leads – see current range in the catalogue.
Clapham 020 7720 8868 Raynes Park 020 8946 5558
100A Switch Isolator